The invention relates to a vacuum valve including a valve housing which comprises a valve opening, which comprises a longitudinal axis, and a valve seat which surrounds the valve opening, a closure member which is adjustable between an open position, in which the vacuum valve is open, and a closed position, in which the vacuum valve is closed, a valve rod on which the closure member is mounted and which is axially adjustable in a displacement direction and in an opposite direction for adjusting the closure member between the open position and the closed position, an elastic seal which is arranged on a front side of the closure member or on the valve seat of the valve housing, a sealing surface which is arranged on the valve seat of the valve housing or on the front side of the closure member, and against which the seal abuts in the closed position of the closure member, and at least one support part which is arranged on a rear side of the closure member remote from the valve seat and comprises a support surface which is supported on the valve housing in the closed position of the closure member, wherein the abutment between the support surface and the valve housing is effected in an abutment plane which is inclined in relation to the displacement direction about an axis which is at right angles to the displacement direction and at right angles to the longitudinal axis of the valve opening.
A vacuum valve of this type proceeds from U.S. Pat. No. 7,011,294 B1. In the case of the vacuum valve described in this publication, the closure member is realized in a wedge-shaped manner and is displaced as a result of an axial displacement of the valve rod, on which the closure member is mounted, between its open and closed position. Sliding and spacer parts are arranged on the front side of the closure member next to the seal. These sliding and spacer parts as well as the support parts arranged on the rear side of the closure element form a sliding bearing arrangement for the closure member when closing the valve over a last part portion of the adjustment path of the closure member up to achieving the closed position of the same. In spite of the shear stress acting on the seal when the vacuum valve is closed, a service life for the seal that is sufficient for many applications can be achieved in this connection. Even the particle generation can be kept to a sufficiently low level.
In the case of many types of vacuum valves, attempts are made, in contrast, to avoid shear stress on the seal as much as possible. In this connection, L-valves, pendulum valves, butterfly valves and sliding valves with expanding members are known in various embodiments.
Due to the manufacturing tolerances of the valve housing and/or of the closure member, in the case of the vacuum valve disclosed in U.S. Pat. No. 7,011,294 B1, the seal can be pressed in a non-uniform manner over its periphery, in particular where the closure member has a larger nominal width. This can result in the closed vacuum valve not sealing fully and/or the seal being exposed to increased local stresses, as a result of which the wear thereof increases and the service life is reduced. U.S. Pat. No. 7,011,294 B1 also discloses an embodiment where a roller, which interacts with a wall of the valve housing, is rotatably mounted on the rear side of the closure member. This realization, however, also has disadvantages, among others with regard to the existing linear support on the wall of the valve housing and the high level of locally acting forces connected to this.